Structural and gelling properties of whey proteins influenced by various acids: Experimental and computational approaches

Linlin Zhang, Zhuo Zhang, Stephen Robert Euston, Bo Li, Erhu Li*, Caixia Fu, Guodong Chen

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)

Abstract

Five different acids, i.e., hydrochloric acid (HCl), acetic acid, lactic acid, γ-aminobutyric acid (GABA) and taurine were applied to investigated their effects on heat-induced gelation properties of whey protein isolate (WPI) at pH = 5.5. All WPI gels were found to have self-similar structures with the fractal dimension, df = 2.40. Those denatured WPI formed strong physical gels that were susceptible to shear and strain. Of all the acids, HCl, GABA and taurine significantly strengthened WPI gels. Moreover, denser packing of protein aggregates was observed from the gels with GABA and taurine. Besides experimental approaches, molecular dynamics (MD) simulations were also applied to investigate the effects of various acids on denaturation of β-lactoglobulin (β-LG). GABA and taurine were found to protect β-LG from denaturation and delayed the molecular heat-induced unfolding. Moreover, presence of HCl, GABA and taurine conserved the rigidity of unfolded β-LG and localized the residue –SH121, which was believed to result in promoted reaction-limited clustering aggregations (RLCA) of β-LG molecules and strengthened WPI gels. Further studies suggested that there was no strong binding or aggregation between cations (Na+) or anions/zwitterions and β-LG molecule. Therefore, the effects from various acids (anions/zwitterions) on β-LG and WPI were supposed to result from long-distanced electrostatic interactions and/or their effects on the protein hydration shells.
Original languageEnglish
Article number109003
JournalFood Hydrocolloids
Volume144
Early online date27 Jun 2023
DOIs
Publication statusPublished - Nov 2023

Keywords

  • Gelation
  • Molecular dynamics
  • Organic acid
  • Rheology
  • β-lactoglobulin

ASJC Scopus subject areas

  • Food Science
  • General Chemistry
  • General Chemical Engineering

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